Multistage low temperature coke apparatus



Oct. 13, 1931. Y H. fc. HoLTHoFF 1,827,199

MULTISTAGE Eow TEMPERATURE CORE APPARATUS Filed May 25. 1927 4 Sheets-Sheet 1 ATT OMEY I. N WN mw@ uw wat d@ A W o E::E:: :Ezzizzz: E :Ezzz:: :z ::E=: o NQ l 1 l I l l l- 3v u E, n MM w .r h `1 t IIZ ME M I l.mm I l m|| hx@ um ux E N QE .Smm

Oct. 13, 1931. y ema. c. HOLTHOFF 1,827,199

MULTISTAGE LOW TEMPERATURE COKE APPARATUS Filed May 25. 1927 `4 Sheets-Sheet 2 IN VE NTOR www ACTORNEX Oct3 13, 1931. l H. c. HOLTHOFF i 1,827,199

MULTISTAGE LOW TEMPERATUR COKE APPARATUS Filed May 23, 1927 4 Sheets-Sheet 5 IN vfN r'oR /zfE/vny C. Ho/.r/forf: l

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ATTORNEY.

Oct. 13, 1931. H. c. HoLTHoFF 1,827,199

MULTISTAGE Low TEMPERATURE COKE APPARATUS I Filed May 23. 1927 4 Sheets-Sheet 4 @d @Xy/gz INVENTOR Hmm C. HOL Mor/ ATTORNEY.

Patented Oct. 13, 1931 a 4 UNrrlt-:n STAT.

,s PATE-Nr ort-'1ct'.

HENRY c. HoLTHoFr. or LONG BEAC. cALIFonNIA, .essreNoa-'ro BENJAMIN s.

THAYER, 0F PHILADELRHIA, -PENNSYL'VANIA- MULTISTAGE LOW TEMPERATURE COKE APPARATUS Application Aiiled May 23, 1927. Serial No. 198,699;

In the manufacture of low temperature coke the commercial plants heretofore in use were not commercially successful due to certain inherent faults, among which are the following: A lack of large capacity, the exposure of metallic parts to high temperatures, excessive cost of operation and maintenance, and so forth.

An object of my invention is .to provide a furnace for the manufacture of low temperature coke which has a large capacity, the metal parts .of which are not exposed to high temperatures, and the cost of maintenance and operationA being relatively low.

Another object is to provide a multi-stage furnace of the character stated in .which the coal is continuously fed from one stage to another without interruption and without loss of heat. Y

Another object is to provide a furnace in which the coal is transferred to vvarious stages, such transfer being effected prior to. a change in the physical characteristlcs of the coal due to the change in temperatures. .That is, at lower temperatures a drying effect is had on the coal, at the next higher temperatures a certain portion of the volatile constituents are released, and at the higher temperatures the coal is in a plastic state. It is obvious that a single stage furnace is not applicable to handling the coal in these various stages'n an effective and economical manner.

A still further object is to so handle the coal that the heat transfusion therethrough will be rapid and complete, and also that during the plastic stage the cross-section of the mass will be relatively small, thus insuring a more complete release of the volatile con-l stituents and forming a more compact and commercially useful product.

A still further object is to conduct the coal through a muiie, at the higher temperatures, in a thin layer and without agitation so as to effect a cementing of the coal into a compact mass and to facilitate the evolution of the volatile constituents.

An advantage of my invention-` is to decrease the time required for the complete carbonizat-ion of the coal over the methods Fig. 2 is an enlarged vertical sectional View taken on line 2, 2, Fig. 1.

Fig. 3 is an enlarged vertical sectional view taken on line 3, 3, Fig. 1.

Fig'. 4 is a vertical sectional View taken on line 4, 4, Fig. 2, to the same scale as Fig. 1.

Fig. 5 lis a fragmentary side elevation of the conveyor chain and driving head.

Fig. 6 is a fragmentary vertical sectional view of the muilie showing the compression drag plate;

Fig. 7 is a fragmentary vertical sectional view taken on line 7, 7, Fig..6.

Fig. 8 is a fragmentary vertical sectional view of the muie showing a compression roller which may be substituted for the plate shown in Fig. 6. v

Fig. 9 is a fragmentary vertical sectional view taken on line 9, 9, Fig. 8.

0 Referring more particularly to thedrawings:

My furnace consists first in a drying and pre-heating lunit 1 which comprises an upwardly inclined housing 2 in which a screw conveyor is mounted. The shaft of the conveyor 3 is provided with gear 4 on the lower end thereof and a drive .weer 5 meshes with the gear 4 and is driven oy an independent source of power, not shown. A feed hopper 6 extends into the lower end of the housing 2 through which the' coal is fed. A pipe 7 en tends from the upper end of the housing 2 to conduct the moisture out of said housin The housing 2 is mounted on a brick i'due wall 3, which iiue has a passage 3 extending under the trough 2, and the waste gasses pass from a duct 10 into the passage 9, thus heating the lli housing 2 and its contents. Down passages 11, 12 entend from either end of the passage 9 to stach chamber 13. A damper 14 is rovided in the chamber 13 to regulate the ow of waste gasses, either through Athe'chamber 2 or directly to the staclr chamber 139 as may be desired.

The coal, after being fed into the housing 2 and conveyed there through by the screw conveyor 3, is dried and pre-heated and the moisture is removed therefrom. 'llhis operation is eected by the heat of the waste ilue gasses, thus economizing on the heat and preparing the coal for the second unit. At the top of the housing 2, ll provide a cross-conveyor 15 which dumps the coal into the end of a stationary horizontal retort 16. 'llhe retort 16 is preferably constructed of ovoid cross-section and is provided on the exterior thereof with a spiral rib 17` A briclr jacket 18 surrounds the retort 16 and is spaced therefrom the depth of the rib.. 17, thus providing a spiral heating passage 19 the purpose of which will be further described. Within the retort 16 ll position a horizontal rotor 20 which is suitabl journaled and is rotated through the me ium of the gear 21 secured thereto, which gear is actuated from a suitable source of power not shown.

The rotor 20 is provided on its outer surface with aspiral conveyor flight 22, whlch conveyor is adapted to move the coal from the rear of the retort 16 to the forward end of, as will be further-described. A burner 23 extends into the forward end ofthe rotor 20 and spplies heat thereto, and a thrust bearing 24 is provided adjacent the rear en d of the rotor 20 so that the expansion of said rotor is forwardly. 'llhe passage 10 above referred to extends from the rear end of the rotor 2O to the passage 9, as shown in lFigs. and 4.

ln the drying and pre-heating unit the temperature of the coal is raised to slightly below the point of distillation, while in the 'second unit the temperature in the coal is raised to slightly below the point of 'agglomaygr eration. During the passage of the coal through the second stage, a certain quantity of the volatile constituents thereof will be released and a plurality of outlet vents 25, 26 are provided in the retort 16, which vents are connected to suitable condensers (not shown) teenies for the recovery of the valuable ley-products.

1n order that the heet may rapidly penetrate, or transfuse entirely throu h the mass or coal during the second stage, 1f it is. found desirable to stir, or agitate the same, this action may he provided for by an interrupted screw conveyor.

.After the coal has traversed the length of the retort 16 it drops through a vertical passage 27 extending downwardly to a mums 28. in the mume 23, i provide a conveyor 29 which passes through the mufde on the floor 30, and l asses over sprockets 31, 32 at either end of the muiile. l'he return reach of the -fconveyor passes under the inutile through a tunnel 33 and rests on a plurality of rollers 34. 'llhe shaft of the driving sprocket 31 is rotated through gear means 35 and driven irom a source of power, not shown.

As the coal enters the forward end of the muiiie 28 i. is spread evenly over the conveyor 29 by suitable spreader means, such as the wheel 36. "A heating :due 37 surrounds the muhde 28 flor approximately one-half the len h thereof, and burners 38 extend into sai due to maintain a temperature in the coal (approximately 416 to 450- degrees 0.). rl`he burners 38 are located under the muiiie 28 adjacent the forward end thereof, and by-passes 39 are provided around the rhume to the re-l turn flue 37 so that the hot 1 ases pass, iirst along the bottom of the mue,'then around the same to the top, thence along the top to a vertical duct 40 which opens into the heatin passage 19 for the heating of the retort 16.

rom the heating passage 19 the gases pass through an outlet vent 41 to the heating duct 10, and thence to the first unit, as previously described. llf the hot gases from the burners 38 are not suihcient to maintain the proper temperature inthe retort 16,1 provide an auxiliary burner 42 in a combustion chamber 43 which opens into the forward end of the passage 19, thus ll can accurately regulate the temperature in the retort.

rlFhe coal enters the mue 28 prior to its plastic or semi-liquid stage, and during its passage through the heated portion of the rhume becomes plastic. llt is essential that during this period the coal should remain in a quiescent state and should not be distugrbed or agitated inorder that it may cement into a homogeneous mass. During the final stage of the coal in its passage through the mule, additional gases evolve therefrom, and the forward end of the muille is open to a chamber 44 from which a vept pipe 45 exl rll`his bar 47 lex- 46 on the surface of the coke. The drag plate serves to break down any froth bubbles 011 the surface of the coke,- as well as to compact the same.

If desired, instead of the drag plate 46 I may provide a roller 49 on the shaft 50,-on which I provide weights 51 to force the roller downwardly against the mass of coke, the result being the same as accomplished by a drag plate.

After the conveyor 29 passes from the heated zone-of the mutlie the coke on the conveyor is cooled rapidly by water cooling pipes 52 inserted in the bottom and top of the Inutile. 'The coke spills off the end of the conve or 29 into an enclosed chute 53 and a shaker ox 5l at the bottom of the chute deposits the coal on a conveyor 55 which carries the same to a storage space.

lt will be evident from the foregoing description that the time of treatment of the coal` in anyone unit, is variable since the through-put of the various units is under control by reason of the individual regulation of the speeds of the dryer conveyor 3, rotor 20, and conveyor 29. Also, the heat in each of the thrce units can be readily adjusted for themaintenance of the proper temperature. Furthermore, during the carbonizmg stage, the coal 1s mamtamed 1n a quiescent state thereby permitting the coke to cement into 'a dense mass.

The operation of my invention will be evident from the foregoing descriptioln It will also be evident from the foregoing description that each stage is particularly suited and corresponds to the peculiar physical characteristics of the coa-l at the particular temperature, and although the coal is separately treated during each stage, my process' is continuous and there isno loss of heat during the transfer of the coal from one stage to another.

Having described my invention, I claim:

1. `A multi-stage low temperature coke apparatus comprising a furnace, a drying and pre-heating unit, a screw conveyor in said unit, means to drive said screw conveyor, a retort, a conveyor' from said drying and preheating unit to said retort, conveyor means in said retort, means to actuate said conveyor from the drying and pre-heating unit to said retort, a muliie, said muiiie being open to the retort, and means to drive said conveyor means in the retort, said furnace having a heating chamber about said muiiie, and a sec'- ond heating chamber about said retort means to heat said second heating chamber, a duct connecting said above n'amed chambers, means to heat said first named chamber, said furnace having a heating chamber about the drying and pre-heating unit, aduct connectingsaid last named chamber and the chamber surrounding the retort.

2. A multi-stage low temperature coke apl means to operate said last named conveyor,

said muiiie being open to said retort at one end thereof whereby the muie is heated, said furnace having a duct extending from the interior of the rotor to the housing whereby the heat is conducted to the housing to heat the same. A

3. `A multi-stage low temperature coke apparatus comprising a furnace, a drying and pre-heating unit including a housing, a conveyor in said housing, means to drive said conveyor, a retort, a conveyor extending from said housing to said retort, a rotor in said retort, a screw fiight on the rotor, means to p heat said rotor internally, means to rotate said rotor, a mule, a conveyor in said muiiie, means to operate said last named conveyor, said mulile being open to said retort at one end thereof, said furnace having a duct extending from the rotor to the housing Whereby the heat is conducted to the housing to heat the same, heating means about said mufle, said furnace having a heating chamber about the retort," and a duct extending from said heating means to said chamber, an exhaust port extending from said chamber to said first named duct, and independent heatc ing means for said chamber. A

4. A multi-stage low temperature coke apparatus comprising a drying and pre-heating unit which includes a housing, a conveyor in' said housing, means to operate said conveyor, a retort, a conveyor extending from said housing to said retort, means to actuate said last named conveyor, a rotor in said retort, means to rotate said rotor, heating means in said rotor, a screw flight on -said rotor, a muflle, a conveyor in saidrmuiiie whereby the coal is carried there through in a quiescent' state, and cooling means at the discharge end ing of said muie and heat conveying means from the furnace to the drying and pre-heating unit, the retort and the muftle.

5. A multi-stage low temperature coke ap- I4 paratus comprising a furnace, a drying and pre-heating unit which includes a housing, heat conveying means from the furnace and extending around the housing, a conveyor in said housing, means to operate said conveyor, a retort,a conveyor extending from said housing to said retort, means to actuate said last named conveyor, a rotor in said retort, means to rotate said rotor, heating means in said rotor, a screw flight on said rotor, a muiile, a conveyor in said muilie whereby the cial is carried therethrough in a quiescent vat sie

state, and cooiing Ineens at the discharge end of said munie, means adapted to compress the coito in the munie, heat means about the charging end of said munie, said furnace having a heating chamber about the retort, a duct eatending rom the muie heating means to the chamber, a second duct extending from the rotor to the housing, an outlet port entending from the heating chamber to said tast named duct, and inde endent heatin' means for heating said cham er about the retort.

5. A matti-stage iow temperature cohe apparatus comprising a furnace, a' housing, heat conduit means from the furnace to the housing, a screw conveyor in said housing, means to rotate said screw conveyor, said housing having `a vent therein, a retort, ar spiral rib extending from the outer surface of said retort, whereby a spiral heating chamber is formed about the retort9 a con'- veyor extending from said housing to said retort, means to actuate said last named conf veyor, a rotor in said retort, means to rotate said rotor, a burner in one end o" said rotor, a mutide, al continuous conveyor in said inutile, means to actuate said continuous conveyor, said mtime being open to the retort at one end thereof, heat means surrounding the charging end ont said mums, said furnace aving a duct extending from said heating means to said spirali` heating chamber about the retort, a drag plate in said `munie adapted to compress the coke on the conveyor, a spreader wheel in said mums, a vent chamber open to the mums, and a vent pipe extending from the vent chamber, vent plpes extending iroin said retort.

7. A ymulti-stage low temperature coke apparatus comprising a furnace, a housing, heat conduit means from the furnace to the housinga screw conveyor in said housing, means to rotate said screw conveyor, said housing having a vent therein, a retort, a spiral rib extending from the outer surface of said retort whereby a spiral heating chamber is formed about the retort, a conveyor extending from said housing to said retort, means to actuate said last named conveyor, a rotor in said retort, means to rotate said rotor, a burner in one end of said rotor, a mue), a continuous conveyor in said rhume, means to actuate said contlnuous conveyor, said muf- 'ie being open to the' retort at one end there i-IL'ENRY CC. HLTHQFF. 

